False twister head



' g- 1967 A. s. PETERSON ETAL 3,3 8

FALSE TWISTER HEAD 2 Sheets-Sheet 1 Filed June 13, 1966 INVENTORS Norman H. Mable By Arnold 6. Peterson PJM+EM ATTORNEYS 1957 A. cs. PETERSON ETAL 3,334,481

FALSE TWISTER HEAD Filed June 13, 1966 2 sheetsw-sheet 2 Fig. 5

INVENTORS Norman H. Mable y Arnold G. Peterson PM -Pmw ATTORNEYS United States Patent 3,334,481 FALSE TWISTER HEAD Arnold G. Peterson and Norman H. Mabie, Claremont, N.H., assignors to L. M. & L. Corporation, Clarenlont, N .H., a corporation of New Hampshire Filed June 13, 1966, Ser. No. 557,097 Claims. (Cl. 5777.3)

ABSTRACT OF THE DISCLOSURE A false twister head insert free of conventional upstanding pins, or teeth, but having a truncated conical recess in the upper end with a smooth, continuous circular, peripheral edge, there being at least two circumferentially spaced teeth within the truncated conical recess, flush with, or below the level of, the smooth peripheral outer edge. The side faces of each tooth are of fiat, triangular configuration and in a vertical plane and the top face of each tooth may slope downwardly and inwardly from the peripheral edge to the bore. The head is of collar, or sleeve, form, and resiliently movable vertically to yield during twisting.

This invention relates to false twist devices used on spinning frames in the textile fiber industry. More particularly, the invention relates to false twist apparatus comprising a novel kind of twister head top.

False twist devices have usually included an elongated tubular body member having a pair of diametrically opposed, axially extending twister pins at the upper end and yarn engaging means at the lower end. They are customarily mounted to rotate on a vertical axis in two fixed, vertically spaced bearings and a whirl or pulley is positioned on the body member, between the bearings, for rotation by a belt. The upper pairs of draft rolls are usually located along the top of the frame and the yarn engaging means of each false twist device is at a close spaced distance above the nip of a pair of lower draft rolls located along the side of the frame. A strand to be drafted passes from the nip of a pair of upper rolls angularly over a fixed rod and then down into the axial bore, or central passage, of a false twist device and thence straight downwardly into the yarn engaging means and the nip of the lower rolls. The lower rolls rotate at a greater surface speed than that of the upper rolls to attenuate, or draft, the strand; the rotating pins of the twist device impart a false twist to strengthen the strand during drafting.

The objects of drafting devices of the prior art have generally been to move the fibers in the strand steadily forward from the upper draft rollers, present the same in order to the lower draft rollers, whereby the yarn will be a thinner attenuated copy of the strand with each fiber displaced an equal amount, and also to correct any irregularities in thickness of the strand in the draft ing zone.

In development of false twist devices of the prior art, considerable attention was given to the twister head top, a rotating member having a bore therein which member repeatedly engages the roving passed into the bore thereof. This rotational movement imparted to the roving by the twister head top effects a false twist. In prior art devices this twist has been effected by pulling the strands over pins on the twister head. Twister heads having such pins are shown in the drawings of U.S. Patents 1,774,371 to Hendrickson et al., 2,740,251 to Bierlin, and 2,972,853 to Lemieux. Emphasis in studying means for improving the operation of twister heads has been in designing twister heads imparting greater draft to the strand, in increasing the life of the twister head, and in reducing the quantity of waste resulting from short fibers dropping out of the roving during the attenuating process effected by the false twist apparatus. Thus Bierlin suggests the use of extremely hard materials such as hard glass or porcelain as well as certain specific configurations for use in manufacture of twister-head tops. However, none of the problems suggested above have been entirely solved by any prior art twister head.

The principal object of the invention is to provide an improved twister head insert having a plurality of recessed projections thereon for engaging the strand to be twisted, the recessed nature of the projections and vertically resilient mounting all tending to reduce waste, strengthen the strand, and avoid breakage.

It is another object of the invention to provide an improved twister head having excellent wearing characteristics.

It is a further object of the invention to provide a twister head having improved operating characteristics with respect to the properties of rovings processed thereon.

Another object of the invention is to provide an improved process for attenuating rovings.

Another object of the invention is to provide improved false twist apparatus which is resilient to fouling by lint.

Applicants have achieved most of these objects by forming a twister head having, instead of the upwardly-projecting pins utilized in the prior art, an upper face with a plurality of tooth members, which members are recessed to be flush with or completely, below the main body of the twister head. Such twister heads, while generally advantageous for use in the textile industry, are exceptionally useful in combination with resilient support means such as that generally described in U.S. Patent No. 2,972,853, and especially with the novel improved resilient support means utilized in the illustrative embodiment of the invention described hereinbelow.

In this application and accompanying drawing, a preferred embodiment of the invention has been shown and described and various alternatives and modifications have been suggested, but it is to be understood that these are not intended to be exhaustive and that other changes and modifications can be made within the scope of the invention. These suggestions herein are selected and included for purposes of illustration in order that others skilled in the art will more fully understand the invention and the principles thereof and will be enabled to modify it and embody it in a variety of forms, each as may be best suited to the condition of a particular case.

FIGURE 1 is a false twist apparatus according to this invention, in half section.

FIGURE 2 is an enlarged plan view of the improved twister head, or insert, of the invention.

FIGURE 3 is a side elevation of the head shown in FIGURE 2, in section on line 3-3 of FIGURE 2.

FIGURE 4 is a side elevation of the head shown in FIGURE 2, in section on line 4-4 of FIGURE 2.

FIGURE 5 is an enlarged side elevation, in half section, of the collar in which the head is seated.

FIGURE 6 is a bottom plan view of the collar shown in FIGURE 5, and

FIGURE 7 is a side elevation of another embodiment of the twister head insert of the invention, in half section.

Referring to FIGURE 1, it is seen that a pair of upper, or feed, draft rolls 20 and 21 are mounted along the top of a spinning frame of a type commonly used in woolen mills but not shown here because it is no part of the instant invention and because its presentation would add nothing to the understanding of the invention by those skilled in the art. Rolls 20 and 21 have a nip 23 and are being rotated'at a predetermined speed by a drive mechanism not shown.

A pair of lower draft rolls 24 and 25 having a nip 26 are mounted below rotatable false-twist apparatus 28. Rolls 24 and 25 rotate at such a speed that roving 30 is carried therethrough at a greater linear velocity than the velocity at which it passes through rolls 20 and 21.

Hollow frame member 32 of false twist apparatus 28 is caused to rotate about its axis by means of a belt (not shown) engaging pulley member 33. Pulley member 33 is held in engagement with hollow frame member 32 of apparatus 28 by set screw 34.

Within frame member 32 is a hollow tube 35, having a strand guide bore 37 therein, and having a spring 36 coiled thereabout. Spring 36 is supported by an internal shoulder 38 within frame member 32 and provides means for holding collar 40 in biased relationship with frame 32.

Collar 40 is slideably mounted outside of frame 32 and held in the desired position relative thereto by the engagement of axially extending lugs 42 in corresponding axially extending grooves 43 cut into frame 32 so as to cause the collar 40 and tube 35 to be axially slideable relative to frame 32 while being rotatable therewith (FIG- URE 6). As seen in FIGURE 5, collar 40 is machined to provide surfaces 44 on which twister head 46 is cemented into position with an adhesive, for example, that sold under the trade name Eccobond. Passing through collar 40 and snugly fit to collar 40 at surfaces 48 is tube 35 adapted for vertical yielding action within frame 32 as the tension on spring 36 varies.

Bushing 51 holds tube 35 in centered position with respect to frame 32. A lower retaining ring 52 encircles tube 35 and provides means for limiting the upward travel of tube 35, collar 40, and twister head 46 by engagement with bushing 51. An upper retaining ring 53 is mounted on frame 32 and serves to limit upward travel of pulley 33 should it loosen from frame 32.

Yarn engaging means comprises fixed jaw 54 and jaw 56 pivotally mounted on pivot pin 57. The latter, counterweighted with weight 58, is mounted at the bottom of the apparatus. Weight 58, through centrifugal action imparted thereto by the spinning of the false twist apparatus, imparts a grip of increasing pressure on strand 30 by jaws 54 and 56 as the weight moves outwardly from frame 32.

Thus, in following a strand through the false-twist apparatus, the following is observed:

After leaving rolls 2]. and 20, the strand is drawn under tension into the axial bore 6%) of twister head 46. As it enters bore 60 it is hit and twisted by the toothed surface 61 of the twister head and thence carried at accelerated linear speed down through the inside of hollow tube 35, pressed between jaws 56 and 54, and delivered from between rolls 24 and 25.

A particular advantage of the embodiment of the invention described above is its relative freedom from lint contamination. This advantage is primarily achieved by elimination of upwardly-facing crevices between working surfaces which were present on resiliently mounted falsetwist apparatus known to the prior art. Thus, referring to FIGURES l and 5, lugs 42 on collar 40 engage and slide downwardly over grooves 44 an the outer periphery of frame 32.

As has been indicated above, the novel twister head is the important aspect of the instant invention inasmuch as the circular peripheral edge and recessed slope of the toothed surface 61 thereon and the excellent slip properties thereof are effective in giving an adequate falst twist at high speed and at exceptionally high drafts with a decreased loss of short fibers from the roving.

Referring to FIGURES 2 to 4, it is seen that a number of radii and planar relationships are critical in constructing a twister head capable of the most advantageous performance, As shown, the twister head, or insert, 46, comprises an annular, elongated body 70, having one end portion 71 shaped and adapted to be seated in the recess 72 of collar 40 by adhesive 73, set screw 69 or any other suitable means. Preferably, body 70 is a hollow cylindrical tube having, at its other end 74, the smOth continuous, peripheral, outer edge, or rim 80, encircling the toothed edge 75 to constitute the irregular surface 61 of this invention.

The toothed edge 75 includes at least three and preferably four spaced upstanding teeth, protuberances, or bosses, 77, i.e. 77a, 77b, 77c, and 77d each separated by a hollow, or depression 79, i.e. 79a, 79b, 79c, and 79d, the teeth and hollows being uniformly spaced angularly around the edge of the head 46.

Unlike the twister heads of the prior art, on which there are pins, projecting above rim level, which rotate into engagement with the tender, easily breakable strand 30, as in the above-mentioned Lemieux patent, No. 2,972,853, or in which there are such projecting pins with rounded edges, as in the abovementioned Bierlin patent, No. 2,740,251, the teeth 77 of the twister head of the invention are flush with or below the level of, and cooperate with, outer support surface 80 of the twister head to provide a relatively gentle but effective twist action. The irregular surface 61, not only imparts the desired twist, but also greatly reduces breakage, down time, lint, and wear on the insert. A particular advantage of the novel arrangement is that more than two teeth 77 may be advantageously incorporated on the same twister head.

Referring to FIGURE 3, it is seen that the outer edge rim of twister head 46 forms a continuous, smooth, circular, support edge 80 over which a roving 30 may be carried into bore 60 and bore 37 along sloped surface 81 of depressions 79. The angle A at which depressions 79 slope from support edge 80 may he from 15, when relatively weak rovings are being processed, to 60, when strong cords and synthetic fibers are being processed. For a moderately strong woolen roving, an angle of about 40 is preferred. For purposes of illustration in FIGURES 2, 3 and 4, an :angle A of 30 has been chosen.

The relationship between the horizontal plane of peripheral edge 80, the plane of the upper edge faces of the teeth 77 and the plane of the truncated conical surface 81 is important in that a roving is so supported and guided by the smooth edge 80 as to permit the elimination of the conventional fixed rod, or guide bar. Each time the roving 30 is successively picked up by a tooth 77, rolled across the leading, flat, triangular, face there-of and spilled off the rounded tooth edge, it is drawn, or attenuated, slightly because the tooth is moving away from the upper drafting rolls. Upon release from the tooth, the slightly attenuated strand, with twist imparted by the tooth, is temporarily out of contact with the insert until it whips against first the lower rounded edge at the bottom of the next successive depression 79 and then against the upper rounded edge 80 at the top of the depression 79. The lower edge is contacted first due to the downward pull of the nip 26 of the front drafting rolls. Any heavy, or thick, areas in the strand caused to move upwardly toward the nip 23 of rear drafting rolls by this whipping action are not interfered with by the smooth edge 80.

The radii of an especially useful embodiment of the invention illustrated in the drawings are represented in FIGURES 2, 3, and 4, as R R R R and R R R R and R are all about of an inch and R is about & of an inch.

It should be noted that the opposite flanks 83 and 84 of each boss, or tooth, 77, are preferably vertical and parallel to each other, and that the height of the flanks, at the inside, or bore, from the plane of the root to the plane of the point, or top, is at a maximum, while the height of the flank at the outside, or support edge 80, is at a minimum, namely, zero. The flanks are therefore generally triangular in outlineand impact the strand with a flat radially extending face, which imparts increased friction for increased twist as compared with the tangential engagement of the cylindrical pins of the prior art.

Although the unique twister head described above can be fabricated from any of a number of materials including such excellent and expensive materials as ceramics, such as porcelain, steel and the like, it is especially advantageous to use polymeric materials whose surface characteristics, i.e. friction coeflicient and the like are not susceptible to excessive change because of wear, corrosion, or the like. The preferred of such polymers have been found to have a self-lubricating effect when utilized in connection with rovings commonly encountered in the textile industry.

While the solid polymers like nylon or those other solid polymers formed from various organic materials such as propylene and other ethylenically-unsaturated materials such as styrene are useful in forming the toothed twister head of the instant invention, a polyacetal such as that sold under the trade name Delrin or a polyetrafluoroethylene such as that sold under the trade name Teflon is preferred. The acetal copolymer based on trioxane and described in US. Patent No. 3,027,352 is also i. material advantageous for use. These preferred polymers are self-lubricating. For example, they generally lave a c-oeflicient of friction of 0.3 or less on steel as measured by the inclined plane tests known to the art.

Delrin and the fluorocarbon-type polymers are particularly desirable because of their self-lubricating characteristics. The former is particularly long-wearing, and this, combined with its resiliency and excellent slip characteristics, makes it particularly advantageous for twister heads.

In the. illustrated embodiment, the head 40, frame 32, and pulley 33 are all formed of self-lubricating material, such as Delrin, so that the head slides easily on the frame by means of lugs 42 and grooves 44.

A preferred embodiment of the invention is shown in FIGURE 7, in which the smooth, continuous, outer, circular rim 80 of twister head insert 46, encircles the truncated, conical recessed surface 81 from which upstand the identical spaced teeth 77. As shown in FIGURE 1, the strand 30 conventionally approaches the head 46 at an angle of about 20 from the horizontal plane 88 of the rim 80, it being understood that the twister head 40 continually rises and falls under tension changes within a limited range, such as one-half inch. The slope of the truncated conical surface 81 is about 60 from the horizontal plane 88 or rim 80, so that the roots, or inner bottoms of the teeth, fall into the plane designated 89. The upper face 90 of each tooth 77 has a slope of about 20 from the horizontal plane 88 of rim 80 so that it is :angularly below the level of the rim 80 an angular distance of about 20, angularly above the plane of surface 81 about 40, and so that the tips, or inner tops 91 of the teeth fall into the plane 92. The flanks 93 are triangular, and the angular relationships of the recessed teeth can be varied to conform with the characteristics of the strand being twisted, for example, by sloping the upper faces 90 of the teeth at and the truncated conical face 81 at 40 to form teeth 30 in angular height from root to tip.

What is claimed is:

1. In apparatus for imparting false twist to a roving being subjected to an attenuation step wherein said apparatus comprises a rotatable twister head having an axial bore therein, a rotatable tube also having a rotatable bore therein for passage of said roving therethrough, and a means for exerting pressure on said roving after it emerges from said rotatable tube,

the improvement comprising a twister head having an upwardly-facing toothed surface for false twisting engagement with said roving as it enters said twister head, said surface including a smooth, continuous, outer, upper edge encircling said toothed surface; and

a plurality of uniformly spaced, identical alternate upstanding teeth and depressions, each depression having a radially and downwardly sloped surface between adjacent teeth and said sloped surfaces each extending from said smooth outer edge of said twister head to said ,bOre.

2. An apparatus as defined in claim 1, wherein said radially and inwardly sloping surfaces of said twister head are at an angle of between 15 and 60 from the horizontal.

3. An apparatus as defined in claim 1, wherein the upper face of each tooth slopes inwardly and downwardly below the plane of the said outer upper edge at a predetermined angle of slope.

4. An apparatus as defined in claim 1, wherein said twister head is constructed of self-lubricating polymeric resin.

5. In apparatus for impartingfalse twist to a roving being subjected to an attenuation step wherein said apparatus comprises a rotatable twister head, a rotatable tube having an axial bore therein for passage of said roving therethrough, and a rotatable frame in respect to which said twister head and said tube are mounted in biased relationship for resilient axial motion relative to said frame and in response to changing tension exerted by said roving on said twister head,

the improvements comprising (1) a collar for holding said twister head and said tube, an inner cylindrical section of said collar facing downwardly for slideable movement along the exterior of said rotatable frame, thereby preventing entrapment of falling lint and the like between said collar and said frame, and (2) a twister head having an upwardly facing toothed surface comprising a plurality of teeth and inwardly and downwardly sloping surfaces between said teeth.

6. A twister head comprising an annular body generally outlining a hollow cylinder,

one end of said body being adapted to be seated in a rotatable false twist tube assembly,

the other end of said body having a truncated conical recessed end face and having a smooth, continuous, circular, outer, peripheral edge,

said truncated conical recessed end face including at least two diametrically opposite, integral, upstanding tooth-like protuberances spaced apart by a corresponding number of depressions,

the flank of each said tooth-like protuberance constituting a flat, generally triangular strand twisting face for imparting false twist to said strand.

7. A twister head insert comprising an annular elongated body having one end portion adapted to be seated in a twister tube, and having a smooth, continuous circular outer rim encircling a truncated conical recessed surface at the other end thereof,

said truncated conical surface having at least two upstanding teeth, uniformly spaced therearound, the tops of said teeth being in a first plane no higher than the level of said rim, and the roots of said teeth being in a second plane well below said first plane at the bore of said tube, said planes being spaced apart a predetermined distance,

said insert having a bore identical in diameter with the bore of said tube to form an unobstructed strand path therealong.

8. A twister head insert comprising an annular elongated body adapted to be seated in a false twist assembly, said insert having an exposed, strand-twisting end;

said end including a continuous, circular smooth outer, upper rim encircling a truncated conical recessed surface,

said surface including four upstanding identical teeth,

each having a vertical, generally triangular flat flank for engaging a strand, and each having a top substantially at the level of, and no higher than, the plane of said rim and .a root in a plane well below said rim plane.

9. A twister head insert comprising an annular elongated body adapted to be sea-ted in a false twist assembly, said assembly having a strand guide passage with a mouth approximately at the level of the bottom face of said body;

said insert having an, exposed, strand-twisting end including a continuous, smooth, outer upper rim encircling a recessed surfiace;

said recessed surface including at least two opposite upstanding teeth, each having a generally triangular fiat flank, each having .a top no higher than the plane of said rim, and each having a root in a plane well below said rim plane,

each said tooth being relatively narrow and separated from adjacent teeth by a relatively wide depression and the inner edges of said depressions, at the level of the roots of said teeth being rounded on a radius of about of :an inch;

whereby a strand to be twisted is guided from said rim downwardly and inwardly to 'the mouth of said passage while being subjected to repeated impacts from said recessed teeth.

10. An apparatus as specified in claim 1, wherein the leading, or strand-contacting, flank of each said tooth is fiat, vertical and generally triangular in configuration, rand all strand-contacting edges of said teeth, and the upper and lower edges of said depressions are rounded with a radius of at least of an inch;

whereby said strand is free of subjection to sharp bends tending to sluff 01? short fibers which form lint.

References Cited UNITED STATES PATENTS 1,728,414 9/1929 Jowett et al. 5777.37 2,321,404 6/1943 McCann 57-77.37 X 2,442,761 6/1948 Drennen 5751 2,740,251 4/1956 Bierlin 57--77.30 2,826,892 3/1958 Gustafson 577'7.3 2,831,313 4/1958 Burns et a1 57-119 2,867,970 1/1959 Richter 5777.3 X 2,972,285 2/1961 Lemieux 57--77.4 X FOREIGN PATENTS 643,789 9/1950 Great Britain.

FRANK I. COHEN, Primary Examiner.

D. E. WATKINS, Assistant Examiner. 

1. IN APPARATUS FOR IMPARTING FALSE TWIST TO A ROVING BEING SUBJECTED TO AN ATTENUATION STEP WHEREIN SAID APPARATUS COMPRISES A ROTATABLE TWISTER HEAD HAVING AN AXIAL BORE THEREIN, A ROTATABLE TUBE ALSO HAVING A ROTATABLE BORE THEREIN FOR PASSAGE OF SAID ROVING THERETHROUGH, AND A MEANS FOR EXERTING PRESSURE ON SAID ROVING AFTER IT EMERGES FROM SAID ROTATABLE TUBE, THE IMPROVEMENT COMPRISES A TWISTER HEAD HAVING AN UPWARDL-FACING TOOTHED SURFACE FOR FALSE TWISTING ENGAGEMENT WITH SAID ROVING AS IT ENTERS SAID TWISTER HEAD, SAID SURFACE INCLUDING A SMOOTH, CONTINUOUS, OUTER, UPPER EDGE ENCIRCLING SAID TOOTHED SURFACE; AND A PLURALITY OF UNIFORMLY SPACED, IDENTICAL ALTERNATE UPSTANDING TEETH AND DEPRESSIONS, EACH DEPRESSION HAVING A RADIALLY AND DOWNWARDLY SLOPED SURFACE BETWEEN ADJACENT TEETH SAID SLOPED SURFACES EACH EXTENDING FROM SAID SMOOTH OUTER EDGE OF SAID TWISTER HEAD TO SAID BORE. 